1. Field of the Invention
The present invention relates to a liquid-feeding device for feeding liquid to an external device such as a liquid ejection unit and a liquid ejection apparatus incorporating the liquid feeding device, such as an inkjet printer head, and more specifically it relates to a technique for stably holding a large amount of liquid without liquid leakage and with a simplified low-cost structure.
2.Description of the Related Art
As an ink-feeding device for use in a conventional printer head, the following device has been known, for example.
FIG. 13 is a sectional view of an internal structure of a first example of a conventional ink-feeding device of the type. Referring to FIG. 13, an ink reservoir 201 partitioned into an ink tank 201a and an ink container 201b. The ink tank 201a and the ink container 201b are communicated with each other on the bottom surface.
In the ink tank 201a, ink is contained. On the top of the ink container 201b, a vent hole 202 is formed. Furthermore, within ink container 201b, a porous material 203 is provided for holding ink. Moreover, on the bottom of the ink container 201b, an ink outlet 204 is provided.
If ink is discharged from the ink outlet 204, air enters the ink tank 201a so that the amount of ink corresponding to that of the air is fed to the ink container 201b from the ink tank 201a so as to be held in the porous material 203.
Wherein owing to capillary force of the porous material 203, a force is applied to the ink in a direction absorbing the ink, so that the ink cannot leak from the ink outlet 204.
FIG. 14 is a sectional view of an internal structure of a second example of a conventional ink-feeding device. Referring to FIG. 14, in the same way as the first example, the ink outlet 204 is provided on the bottom of an ink reservoir 205. Also, within ink reservoir 205, a porous material 206 is provided for holding ink. To the porous material 206, a force is constantly applied in directions (arrow directions in FIG. 14) spreading out the porous material 206 with a spring 207. By the force of the spring 207, a force is applied to the ink within the porous material 206 in a direction in that ink is absorbed. Thereby, the ink cannot leak from the ink outlet 204 in the same way as the first example.
As described above, the ink-feeding device for use in a printer head is structured so that ink cannot leak from the ink outlet 204.
However, the conventional technique described above has the following problems.
In the first example, since the porous material 203 is provided within the ink container 201b, the capacity of the ink-feeding device is reduced by the volume of the porous material 203. Therefore, there has been a problem that the ink capacity within the device is small relative to the entire size of the ink-feeding device.
Also, since the second example is a system using the spring 207, there are problems in manufacturing that if the ink reservoir 205 is reduced in thickness, for example, the spring 207 cannot be accommodated within the bag 206, and the manufacturing process is complicated. Furthermore, this is a structure in that the spring 207 is accommodated inside the bag 206, so that there have been problems that the mechanism is complicated and the cost is also increased.